#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
int n;
struct point {
long long x, y;
point () {}
point (long long x, long long y) : x(x), y(y) {}
point operator + (point p) const {
return point(x + p.x, y + p.y);
}
point operator - (point p) const {
return point(x - p.x, y - p.y);
}
} a[maxn];
int ord[maxn];
long long cross(point p, point q) { return p.x * q.y - p.y * q.x; }
long long dot(point p, point q) { return p.x * q.x + p.y * q.y; }
bool inSegment(point a, point b, point c) {
return cross(c - a, b - a) == 0 &&
dot(a - b, a - b) >= max(dot(a - c, a - c), dot(c - b, c - b));
}
int side(point a, point b, point c) {
long long x = cross(b - a, c - a);
if(x > 0) return 1;
else if (x < 0) return -1;
else return 0;
}
bool intersect(point a, point b, point c, point d) {
if(side(a, b, c) * side(a, b, d) == -1 &&
side(c, d, a) * side(c, d, b) == -1) return true;
for(auto i : {c, d}) if(inSegment(a, b, i)) return true;
for(auto i : {a, b}) if(inSegment(c, d, i)) return true;
return false;
}
int main() {
cin >> n;
for(int i = 0; i < n; i++) {
cin >> a[i].x >> a[i].y;
ord[i] = i;
}
auto cmp = [&] (int i, int j) {
return cross(a[i], a[j]) > 0 ||
(cross(a[i], a[j]) == 0 && dot(a[i], a[i]) < dot(a[j], a[j]));
};
sort(ord, ord + n, cmp);
vector <int> res;
set <pair <int, int>> can;
int cur = 0;
while(cur < n) {
int x = ord[cur];
for(int i : {-1, 1}) {
int y = (x + i + n) % n;
if(cross(a[x], a[y]) < 0) {
can.erase(make_pair(y, x));
// cout << "erase " << y+1 << " " << x+1 << endl;
}
}
if(cur == 0 || cross(a[ord[cur - 1]], a[ord[cur]]) != 0) {
bool bad = false;
for(auto i : can) {
if(intersect(a[i.first], a[i.second], point(0, 0), a[x])) {
bad = true;
break;
}
}
if(!bad) res.emplace_back(x+1);
// cout << "check " << x << endl;
}
for(int i : {-1, 1}) {
int y = (x + i + n) % n;
if(cross(a[x], a[y]) > 0) {
can.insert(make_pair(x, y));
// cout << "insert " << x+1 << " " << y+1 << endl;
}
}
cur++;
}
sort(res.begin(), res.end());
cout << res.size() << endl;
for(auto i : res) cout << i << " ";
cout << endl;
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
5 ms |
256 KB |
Output is correct |
| 2 |
Correct |
5 ms |
384 KB |
Output is correct |
| 3 |
Correct |
7 ms |
384 KB |
Output is correct |
| 4 |
Correct |
8 ms |
512 KB |
Output is correct |
| 5 |
Execution timed out |
103 ms |
760 KB |
Time limit exceeded |
| 6 |
Execution timed out |
105 ms |
804 KB |
Time limit exceeded |
| 7 |
Execution timed out |
404 ms |
1144 KB |
Time limit exceeded |
| 8 |
Correct |
71 ms |
640 KB |
Output is correct |
| 9 |
Execution timed out |
231 ms |
1016 KB |
Time limit exceeded |
| 10 |
Execution timed out |
106 ms |
768 KB |
Time limit exceeded |
| 11 |
Execution timed out |
125 ms |
768 KB |
Time limit exceeded |
| 12 |
Correct |
26 ms |
896 KB |
Output is correct |
| 13 |
Execution timed out |
888 ms |
1784 KB |
Time limit exceeded |
| 14 |
Correct |
48 ms |
1528 KB |
Output is correct |
| 15 |
Correct |
61 ms |
1912 KB |
Output is correct |
| 16 |
Execution timed out |
121 ms |
3448 KB |
Time limit exceeded |
| 17 |
Execution timed out |
1092 ms |
4472 KB |
Time limit exceeded |
| 18 |
Runtime error |
94 ms |
5924 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
| 19 |
Runtime error |
95 ms |
5880 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
| 20 |
Runtime error |
98 ms |
5916 KB |
Execution killed with signal 11 (could be triggered by violating memory limits) |
